Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Conference on Lasers and Electro-Optics

Measuring a flying qubit without destroying it

Jeremy L. O’Brien, Geoff J. Pryde, Andrew G. White, Stephen D. Bartlett, Timothy C. Ralph

Published Jan 1, 2004• 0 citations
Publisher

Abstract

We perform a QND measurement of single photon polarization, achieved using measurement-induced nonlinearity. This QND measurement, varied from strong to weak, is used to perform a fundamental test of complementarity in an interferometer.
DOI
10.1364/iqec.2004.itui30

Related papers

Measuring a Photonic Qubit without Destroying It

Geoff J. Pryde, Jeremy L. O’Brien, Andrew G. White +2 more

Measuring the polarization of a single photon typically results in its destruction. We propose, demonstrate, and completely characterize a quantum nondemolition (QND) scheme for realizing such a measurement nondestructively. This scheme uses only linear optics and photodetection of ancillary modes to induce a strong nonlinearity at the single-photon level, nondeterministically. We vary this QND measurement continuously into the weak regime and use it to perform a nondestructive test of complementarity in quantum mechanics. Our scheme realizes the most advanced general measurement of a qubit to date: it is nondestructive, can be made in any basis, and with arbitrary strength.

arXiv:quant-ph/0312048•Physical Review Letters•May 12, 2004•127 citations

Testing Complementarity With Quantum Entangled Photons

Sean J. Bentley

Entangled photons are used to explore complementarity, with one sent through a double-slit without direct observation and the second used to indirectly determine the which-slit information of the first photon.

Frontiers in Optics•Jan 1, 2006•0 citations

Quantum nonndemolition measurement of the polarization of a single photon

Jeremy L. O’Brien, Geoff J. Pryde, AG White +2 more

•Jan 30, 2005•0 citations

Complementarity in a quantum nondemolition measurement

Barry C. Sanders, Gerard J Milburn

We present an analysis of a quantum nondemolition (QND) measurement, which determines which of the two possible paths a photon follows through a Mach-Zehnder interferometer. The measurement is effected by the nonlinear Kerr effect. If a photon traverses the arm of the interferometer containing the Kerr medium, it shifts the phase of a probe beam and then continues through to the interferometer output. The measurement does not destroy the photon but does disturb its phase. Using various probe states, we show how such phase disturbances reduce fringe visibility and enforce a principle of complementarity; the more accurately the QND measurement determines the path of the photon, the lower is the fringe visibility. We determine the appropriate parameters to optimize the observation of the two complementary quantities.

Physical Review A•Jan 1, 1989•76 citations

Testing Quantum Randomness in Single-Photon Polarization Measurements

David A. Branning, Matthew Bermudez

APS•Mar 1, 2010•0 citations

Reply to "Comment on 'Measuring a Photonic Qubit without Destroying It'"

Geoff J. Pryde, Jeremy L. O’Brien, Andrew G. White +2 more

In our Letter we proposed a scheme for nondeterministic quantum nondemolition (QND) measurement of the polarization of a single photon--a photonic qubit--using linear optics and photodetection. The scheme works with nonunit probability, but success is heralded by the detection of a single photon in the meter output. We provided an experimental demonstration of this scheme and introduced three universally applicable fidelity measures--the measurement fidelity F_M, the quantum state preparation fidelity F_QSP, and the QND fidelity F_QND--to quantify its performance. The claim of Kok and Munro in their Comment [quant-ph/0406120] is that one of our fidelity measures F_M is not appropriate because it relies on coincidence measurements. We show why this claim is wrong from both a fundamental and an operational perspective.

arXiv:quant-ph/0507175•Jul 19, 2005•0 citations
Measuring the polarization of a single photon typically results in its destruction. We propose, demonstrate, and completely characterize a quantum nondemolition (QND) scheme for realizing such a measurement nondestructively. This scheme uses only linear optics and photodetection of ancillary modes to induce a strong nonlinearity at the single-photon level, nondeterministically. We vary this QND measurement continuously into the weak regime and use it to perform a nondestructive test of complementarity in quantum mechanics. Our scheme realizes the most advanced general measurement of a qubit to date: it is nondestructive, can be made in any basis, and with arbitrary strength.
We present an analysis of a quantum nondemolition (QND) measurement, which determines which of the two possible paths a photon follows through a Mach-Zehnder interferometer. The measurement is effected by the nonlinear Kerr effect. If a photon traverses the arm of the interferometer containing the Kerr medium, it shifts the phase of a probe beam and then continues through to the interferometer output. The measurement does not destroy the photon but does disturb its phase. Using various probe states, we show how such phase disturbances reduce fringe visibility and enforce a principle of complementarity; the more accurately the QND measurement determines the path of the photon, the lower is the fringe visibility. We determine the appropriate parameters to optimize the observation of the two complementary quantities.
In our Letter we proposed a scheme for nondeterministic quantum nondemolition (QND) measurement of the polarization of a single photon--a photonic qubit--using linear optics and photodetection. The scheme works with nonunit probability, but success is heralded by the detection of a single photon in the meter output. We provided an experimental demonstration of this scheme and introduced three universally applicable fidelity measures--the measurement fidelity F_M, the quantum state preparation fidelity F_QSP, and the QND fidelity F_QND--to quantify its performance. The claim of Kok and Munro in their Comment [quant-ph/0406120] is that one of our fidelity measures F_M is not appropriate because it relies on coincidence measurements. We show why this claim is wrong from both a fundamental and an operational perspective.